A neuropsychological profile of dementia was drafted for individuals with Alzheimer's Disease, Huntington's Disease and 'at risk' for Huntington's Disease. The evaluations extended into memory, learning and perceptual areas, utilizing standard and experimental tasks, also establishing normative references for functional changes encouraged by the aging processes. These behavioral data will be collated with biochemical and neuroradiometric measures, and independent indicators of deterioration and dementia will be developed. In collaboration with NINCDS facilities on Guam, the investigation will attempt to study Parkinsonian Dementia among the indigenous population and compare data with results obtained from demented patients in the U.S.